Timer switch for electric shower

trad

My shower switch has failed. Its a 45 A double pole switch as in a cooker switch, no doubt due to the lenghty showers that my family take.

Here's what I would like to do.

Install a timer where I can regulate the length of a shower to say 10 minutes instead of the nearer 30 minute shower that some have. So when you turn on the shower you have 10 minutes to complete your shower. It has to be capable of handling the power that a shower consumes a Triton T90.

Switch is in a hot press so space is not an issue.

Any suggestions?

aujopimur

Why not go all the way and install a slotmeter

trad

aujopimur wrote: »

Why not go all the way and install a slotmeter

And risk divorce?

Seriously a slot meter type device might work as it would have the components to handle the ampage. Haven't seen any around lately but will do a search.

aujopimur

If you can access the cable overhead fit a Crabtree pullcord switch, these are far more reliable than most of whats available.
If this not an option the next best is an MK wall mounted switch.
With regard to the timer i suggest you consult an electrician as this outside the scope of the DIYer

trad

I've already replaced the wall mounted switch and all in order. I've asked around before with electrical wholesalers and they didn't have any suggestions. I assume I am looking for a relay with a timer fitted? More in the realm of switchgear than domestic electrical I suspect.

davelerave

A push-switch and contactor will work.You'd still need the isolator and you'd have to remember to turn off shower for the next person(when time expires).There may be better ways.
A problem with some controls is that the shower can come back on .I think it would be better if all showers had to be reset at the 'shower unit' after power loss

NotaWiseGuy

You could add a off delay relay to the circuit. Radionics part number
221-092 http://radionics.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=0221092

Leave the control unit in the hotpress. Press a momentary switch wired to the relay. This has to be outside the bathroom and the relay will latch on for the time set. Use that to control a contactor capable of handling the shower. You need to match the break current of the contactor with the MCB on the shower. The parts will set you back most of 200 euro. Add the cost of a sparks. Not a cheap project

trad

Not a cheap project but average ESB bill is currently €250, a lot of this down to 30 to 40 minute showers by the more vain amongst our household. So it may pay for itself in energy saving and, if water metering is on the way, save on water useage.

I'm surprised that there is no "off the shelf" product available. I can't be the only one with this problem ir want's to reduce energy and water useage.

davelerave

The off-delay relay circuit would be good.I'd prob put the 'momentary switch' a distance from shower to prevent users resetting it too easily from bathroom,but not too far away as there's a risk of flooding when it's reset.Fit the standard isolator (45amp switch)as normal.

trad

The 45 Amp switch is in the hotpress, plenty of room for wiring. And they would have to get out of the shower to reset, thats the plan.

Cheeble

Seems to me like you're looking for a technology solution to a non-technology problem.

Tell them not to spend so long in the shower.

Cheeble-eers

Randyleprechaun

The fact that the shower isolator is in the hot press may be part of the reason why it has burned out.

Not allowed as far as I know to have such devices in a hot press, all though it was normal to do so in years gone by.

trad

Probably why pull switches are in use most places now. Original shower was fitted about 15 years ago.

When I find the solution I'm looking for it might be time to upgrade wiring and switch. Thanks for the input.

h2s

Let me know if you have any luck with the timer. I have the same problem. Now I have to go out and get a new switch. I think I'll install a pull switch. But a timer solution would be great.

BTW you can tell daughters that they are spending too much time in the shower, but they don't listen.

trad

I have a buddy who is looking at making up a timer switch but is having a mid life crisis and has gone back to college to do a masters so I'm waiting for him to have a bit of free time to play around. I reckon if he can desigtn one there is a small market for them.

davelerave

i think it's surprising shower controllers (that interrupt the shower)are being sold because of the problem with showers switching back on.It would be fine if the shower unit had to be reset after power loss(to prevent flooding)

Dotsie~tmp

One of the main reasons for shower isolators (45A double pole) burning out is that they are sometimes being used as switches. What I mean by this is that they are being used to interrupt an appliance under load (switched on).

Isolators and not the same as switches. A 45A isolator can carry 45A in a closed position but isn't meant to be able to break it. The arc destroys the contacts over time leading to resistance and catastrophic heating damage. I personally don't even trust the the ratings on some of these given how slim and fragile the build seems. I'm seeing more of this as showers over 9kW become more common. Why the hell is such a large element necessary? 7.5kW is plenty for almost every purpose. A selling gimmick I think.

Of course nobody ever admits to turning their cooker or shower off via the isolator instead of the appliance when you ask. For this reason if the money allows its a good idea to use a contractor arrangement to switch anything over 8kW (IMO). The gear is 60 quid extra and you know there will be no comebacks.

I wouldn't be surprised if some showers are needing 2 switch repairs in their lifetime, which means the investment makes sense for the customer too.

trad

Funny I was talking to a sparks last nite who has a lot of industrial experience. He was saying the same that by interupting the current there would be a lot of arching and the contacts will burn out in no time.

Guess I'll just have to keep shouting up the stairs or turning on the cold tap.

davelerave

Dotsie~tmp wrote: »

One of the main reasons for shower isolators (45A double pole) burning out is that they are sometimes being used as switches. What I mean by this is that they are being used to interrupt an appliance under load (switched on).

Isolators and not the same as switches. A 45A isolator can carry 45A in a closed position but isn't meant to be able to break it. The arc destroys the contacts over time leading to resistance and catastrophic heating damage. I personally don't even trust the the ratings on some of these given how slim and fragile the build seems. I'm seeing more of this as showers over 9kW become more common. Why the hell is such a large element necessary? 7.5kW is plenty for almost every purpose. A selling gimmick I think.

Of course nobody ever admits to turning their cooker or shower off via the isolator instead of the appliance when you ask. For this reason if the money allows its a good idea to use a contractor arrangement to switch anything over 8kW (IMO). The gear is 60 quid extra and you know there will be no comebacks.

I wouldn't be surprised if some showers are needing 2 switch repairs in their lifetime, which means the investment makes sense for the customer too.

switching cooker/shower off/on via contactor could create a hazard.you still need an isolator anyway.

Dotsie~tmp

Contactors are way more reliable than load circuit isolators. They can break under load. You still have to isolate. You are just using a 10A switch instead. Thats how the contactor is pulled in.

davelerave

making/breaking the load on showers/cookers via contactor could cause a flood or fire as appliance is switched on

Dotsie~tmp

Im not sure what u mean. The 10A switch, contactor arrangement is acting as an isolator just as the in circuit 45A DP isolator. The difference being mechanical wear is almost eliminated, and the 40A+ contactor has a far longer lifespan than the 45A isolator. This arrangement is never meant to break under load, just isolate. It does however have a far higher tolerance to improper use by the customer. The chance of fire or flood is no different. Its just a "switch" in the end.

BTW this method is now reccommended by ECSSA for isolation of high load domestic appliances.

Chicken Run

or do what my dad did and install a push-button operated shower like those at the swimming baths.......

Dotsie~tmp

As in a pumped shower? No heating element just a pump? This would be irrelevant as the topic is on high load isolators burning out. Theres a reson why people select instantaneous showers. Usually lack of suitable water heating system.

I do agree that these showers are better if your heating system is compatible.

davelerave

no prob.i thought the contactor couldn't be used to isolate?